Topological phases in N-layer ABC-graphene boron-nitride moire superlattices

Abstract

Rhombohedral $N=3$ trilayer graphene on hexagonal boron nitride (TLG/BN) hosts gate-tunable, valley-contrasting, nearly flat topological bands that can trigger spontaneous quantum Hall phases under appropriate conditions of the valley and spin polarization. Recent experiments have shown signatures of C = 2 valley Chern bands at 1/4 hole filling, in contrast to the predicted value of C = 3. We discuss the low-energy model for rhombohedral N-layer graphene (N = 1, 2, 3) aligned with hexagonal boron nitride (hBN) subject to off-diagonal moire vector potential terms that can alter the valley Chern numbers. Our analysis suggests that topological phase transitions of the flat bands can be triggered by pseudomagnetic vector field potentials associated to moire strain patterns, and that a nematic order with broken rotational symmetry can lead to valley Chern numbers that are in agreement with recent Hall conductivity observations.

9 pages, 6 figures

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Cited by in corpus (5)

• Quantum Metric Induced Phases in Moiré Materials
• Topological flat bands in rhombohedral tetralayer and multilayer graphene on hexagonal boron nitride moire superlattices
• Higher-order Bragg gaps in the electronic band structure of bilayer graphene renormalized by recursive supermoiré potential
• Orbital Hall Conductivity in a Graphene/Haldane and Haldane/Haldane Bilayers
• Electric field tunable bands in doubly aligned bilayer graphene hBN moire superlattice